RE: IR for cable TV decoders ?

["Keith Doxey" <ukha@xxxxxxx>]

Hi Tim,

2&3 sort of "are the same". There are different speeds and
protocols in use
for IRDA

4 could just be "1" with a much higher carrier frequency or it
could be IRDA
or it could be RF for some high end kit.

The problem is that IRDA was only ever designed for short (<2m) range
communication. IRDA receivers have a very narrow reception angle (typically
< 30 degrees) which means you must be close and on axis to receive the
data.

This is contrary to the way normal TV remotes operate where you point it
somewhere in the room and 99% of the time it works a treat.

There is also another major difference in that normal IR uses a modulated
carrier but IRDA uses very short unmodulated pulses. The difficulty is in
making a repeater that handles all types of IR RELIABLY.

Keith



-----Original Message-----
From: Hawes,Timothy Edward (GEG) [mailto:haweste@xxxxxxx]
Sent: 05 February 2002 07:44
To: 'ukha_d@xxxxxxx'
Subject: [ukha_d] IR for cable TV decoders ?



I've got a suggestion, but please bear with me as I clarify my
understanding
.. . .

I haven't followed (and don't completely understand) _everything_ that's
been said on IR distribution / repetition, but AIUI there's a couple of
different "types" of IR.

1. IR that most TVs, videos, CD players etc. use,
2. IR that the cable TV decoders use (is this IRDA, & what does the
"DA"
stand for ?)
3. IR that connects mobile phones to laptops etc. (is this still IRDA or
something else ?)
4. IR used by some high-end hifi equipment

Are 2, 3 & 4 all the same ?

(Again all AIUI) but the problem with "repeating" IRDA is the
sourcing of an
appropriate IR receiver to feed signals into the distribution network ? Or
the sourcing of an IR _and_ IRDA receiver ?


Ok, so now to my suggestion,

A CPC "Price Breakers" catalogue came through my door yesterday
& on the
front cover is a "Universal remote control" (CH48014) which
states it's
suitable for cable receivers. It costs less than a tenner and states that
it's easy to "program" and includes a "scan " facility.

Does this mean it's got a suitable IR(DA?) receiver & emitter to allow
it to
work with cable boxes ? Could this be cannibalised to remove the necessary
parts which can then be incorporated into a structured wiring IR
distribution network ?


Apologies if this has already been discussed before, just seemed another
option.


Thanks,

Tim.

+


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